The major objective of this research project is to understand the manner in which structural macromolecules such as collagen are synthesized by cells, the processing of these proteins both inside the cells and in the extracellular matrix and the way in which the cell interfaces with its environment. We have chosen to focus on procollagen and will be engaged in an analysis of its structure, the factors involved in its secretions by the cell and the processing of the protein extracellularly. We expect to identify and study patients with defects in collagen metabolism. We will also attempt to determine the factors that influence the synthesis of different procollagen types by smooth muscle cells and the role of connective tissue deposition in atherosclerosis. BIBLIOGRAPHIC REFERENCES: Muir, L.W., Bornstein, P., and Ross, R. A presumptive subunit of elastic fiber microfibrils secreted by arterial smooth muscle cells in culture. Eur. J. Biochem. 64:105-114, 1976. Byers, P.H., Narayanan, A.S., Bornstein, P., and Hall, J.G. An X-linked form of cutis laxa due to deficiency of lysyl oxidase. Birth defects: Original Article Series, XII, #5:293-298, 1976.